drivers: display: ili9xxx: add justification for default rotation

To align with udpated ssd16xx bindings.

Signed-off-by: Sven Depoorter <[email protected]>

Author: Snevzor

dts/bindings/display/ilitek,ili9xxx-common.yaml

@@ -28,6 +28,7 @@ properties:
       - 270
     description:
       Display rotation (CW) in degrees.
+      If not defined, rotation is off by default.
 
   display-inversion:
     type: boolean